Question

In the figure acceleration of bodies $A,B$ and $C$ are shown with directions. Values $b$ and $c$ are w.r.t. ground whereas $a$ is acceleration of block $A$ w.r.t. wedge $C$. Acceleration of block $A$ w.r.t. ground is

• A. $\sqrt{(b+c{)}^2+a^2}$
• B. $c-(a+b)\cos \theta$
• C. $\sqrt{(b+c{)}^2+c^2-2(b+c)\cdot c\cdot \cos \theta }$
• D. $\sqrt{(b+c{)}^2+c^2+2(b+c)\cdot c\cdot \cos \theta }$

Answer 1

Answer: (C)

$a=b+c$
Net acceleration of $A=\sqrt{a^2+c^2+2ac\cos (\pi -\theta )}$ $=\sqrt{(b+c{)}^2+c^2-2(b+c)\cdot c\cdot \cos \theta }$